In this work, some novel methanofullerene derivatives of the formula [6,6]-phenyl-C-61-(CH2)(n)-COOR, where n = 2, R=C4H9, C3H7, C2H5, CH3, CH2C6H5, CH(CH3)(2), have been studied together with the reference compound PCBM (n = 3 and R=CH3). We have measured the dependence of polymer photoluminescence (PL) in the blends of poly(2-methoxy-5-(3'7'-dimethyloctyloxy)-1,4-phenylene-vinylene) (MDMO-PPV) and new fullerene derivatives, as well as PCBM and C-60, on the concentration of fullerene. Strong PL quenching due to the photoinduced electron transfer was observed for all fullerenes studied. The derivatives with R=C4H9, C3H7, and C2H5 showed a snore effective quenching than PCBM and C-60. This means that the novel metanofullerens may be selected as good acceptor materials for organic photovoltaic cells.